Copy files

src/helper/clamp.ts

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+export const clamp = (value: number, min: number, max: number): number =>
+  Math.min(max, Math.max(min, value));
+
+export const clamp01 = (value: number): number => Math.min(1, Math.max(0, value));

src/helper/delta-time-calculator.ts

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+export class DeltaTimeCalculator {
+  private previousTime: DOMHighResTimeStamp | null = null;
+
+  constructor() {
+    document.addEventListener('visibilitychange', this.handleVisibilityChange.bind(this));
+  }
+
+  public getNextDeltaTime(currentTime: DOMHighResTimeStamp): DOMHighResTimeStamp {
+    if (this.previousTime === null) {
+      this.previousTime = currentTime;
+    }
+
+    const delta = currentTime - this.previousTime;
+    this.previousTime = currentTime;
+    return delta;
+  }
+
+  private handleVisibilityChange() {
+    if (!document.hidden) {
+      this.previousTime = null;
+    }
+  }
+}

src/helper/last.ts

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+export function last<T>(a: Array<T>): T | null {
+  return a.length > 0 ? a[a.length - 1] : null;
+}

src/helper/mix.ts

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+export const mix = (from: number, to: number, q: number) => from + (to - from) * q;

src/helper/random.ts

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+// source:
+// https://stackoverflow.com/questions/521295/seeding-the-random-number-generator-in-javascript
+// Mulberry32
+
+export abstract class Random {
+  private static _seed = 42;
+
+  public static set seed(value: number) {
+    Random._seed = value;
+  }
+
+  public static getRandom(): number {
+    let t = (Random._seed += 0x6d2b79f5);
+    t = Math.imul(t ^ (t >>> 15), t | 1);
+    t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
+    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
+  }
+}

src/helper/to-percent.ts

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+export const toPercent = (value: number) => `${Math.round(value * 100)}%`;

src/helper/wait.ts

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+export const wait = (ms: number): Promise<void> => {
+  return new Promise<void>((resolve, _) => setTimeout(resolve, ms));
+};